Pedigree Selection


Breeding Home Page		Pedigree Selection
Corn Improvement 2008 State Trials 2008 Northeast Region 2008 CentralEast Region 2008 Southeast Region 2008 Larimore 2008 Thompson 2008 Lakota 2008 Prosper 2008 Fargo 2008 Casselton 2008 Forman 2008 Colfax 2008 Barney How to choose hybrids (Feb.1, 2008; Buffalo, ND) 2008 Corn Hybrid Trials Application 2007 State Trials 2007 Oakes 2007 Casselton 2007 Larimore 2007 Fargo 2007 Prosper Breeding History in ND Corn Production Corn Project Leader Publications Research Teaching Corn Project Staff Graduate Students Objectives Breeding Methods Germplasm Adaptation Pedigree Selection Population Hybrids Recurrent Selection Corn Releases Inbred Releases Population Releases PVP Older releases NDSU corn releases after 1979		The use of winter nurseries (to a lesser degree greenhouse) to advance three generations per year and extensive testing (15-20 locations per year) of thousands of genotypes (~20,000 plots) across years (three to six years) as well as student exposure to the inbred line development process is a priority for the NDSU corn breeding program. Sample sizes vary from 5500 to 22,500 individuals depending on the population with a maximum of 50 segregating early maturing populations (F2, S0, BC1, and GEM) per year. NDSU Inbred Lines (Field Day, Fargo, ND) S1 and S2 Lines being harvested in Salta (Guachipas Winter Nursery), Argentina Pedigree selection in corn involved self-pollinating for inbreeding and testing per se (for production purposes) and cross-pollinating to make not only the initial crosses but also to test inbred lines in hybrid combinations for combining ability and release since the end product is a hybrid. At NDSU, approximately 80% of pedigree selection utilizes elite x elite crosses from same heterotic groups, about 5% across heterotic groups, and 15% from germplasm improvement products coming from recurrent selection improved cycles. In the past five years we have released eight early maturing lines. Tobacco Drier for S1 & S2 Selections Guachipas Staff (2006-2007) Kauai Staff (2005-2006) Choice of germplasm for use as source of inbred lines is essential. At least data from 20+ environments is utilized to select sources. Once they are selected, elite x elite crosses are made in our single-cross nursery and F1s are grown in the greenhouse (no need of this process if germplasm source is an improved population from our recurrent selection program). The following summer thousands of F2 individuals (or S0s) per segregating population. F3 and F4 progenies are grown under drought stress in South America and F3s are crossed for initial hybrid testing to one or two testers in Chile, Puerto Rico, Kauai or New Zealand (new potential site). Early generation testing for complex traits (yield, grain moisture at harvest, root and stalk lodging, test weight, and quality traits) complemented with visual agronomic and disease inoculation and screening across locations has allowed us to select from thousands of potential lines. In addition, every summer we screen for emergence percentage and seedling vigor through a rank-summation index across stages and locations that reduce our pollinations and genetic materials in 10-35% depending on the year effect. Early and late testcross generation trials as well as single-cross trials focus on General Combining Ability (GCA) during the initial stages of testing and on Specific Combining Ability (SCA) during final stages of testing. Single-cross trials have two broad objectives: to determine the relative effectiveness of the different recurrent selection methods and line recycling for developing new genotypes than can be used either as hybrids or as germplasm in pedigree selection programs to meet the current standards of the seed industry to provide training and experience for graduate students in conducting selection within breeding nurseries, planning and conducting the production of single-cross seed, and conducting and analyzing single-cross trials repeated over several environments. Trials are in, approx. 90% of the cases, based on lattice designs while the rest of them are based upon RCBD and augmented designs. Split-plot arrangements have been used occasionally for thesis studies. Aerial Photo of NDSU Corn Hybrid and Recurrent Selection Trials Arranged in Lattice Designs (Fargo, south of 19^th Ave N) After years of extensive testing in hybrid combinations as well as intensive selection during the inbreeding process, elite lines are proposed for release. Both the Director and Dean of the AES and the Chair of NDSU Department of Plant Sciences sign to make releases official. Lines are increased for short and long-term cold storage preservation, for Crop science registration, and for PVP protection. As of 2006, NDSU corn inbred lines are not protected by PVP. Distribution of lines is by 50k lots. Most companies have requested seed of all lines released. Inbred Line Trial (Field Day, Fargo, ND) The use of commercial testers within our program has identified specific public-private elite hybrids for the northern Corn Belt. In addition, molecular and field data have suggested that most ND lines have good combining ability with lines derived from several heterotic groups. As a consequence, several companies have requested seed of ND lines for additional testing and their incorporation into private breeding programs. Three agreements were developed by North Dakota Research foundation (NDRF) for this purpose: material transfer agreement, inbred corn research and development agreement, and commercialization and license agreement for managing NDSU corn intellectual property. DNA fingerprinting with SSR markers is carried out on potential lines for NDSU copyright activity control and molecular markers have been useful to demonstrate genetic differences among inbred lines. Inbred trials have been conducted with the purpose to measure all traits needed for PVP protection. Multiple data were often collected for PVP requirements (24 observations per line, over 35 traits per plot, over 40 lines per year.

Pedigree Selection

Corn Improvement
2008 State Trials
   2008 Northeast Region
   2008 CentralEast Region
   2008 Southeast Region
   2008 Larimore
   2008 Thompson
   2008 Lakota
   2008 Prosper
   2008 Fargo
   2008 Casselton
   2008 Forman
   2008 Colfax
   2008 Barney
   How to choose hybrids (Feb.1, 2008; Buffalo, ND)
   2008 Corn Hybrid Trials Application
2007 State Trials
   2007 Oakes
   2007 Casselton
   2007 Larimore
   2007 Fargo
   2007 Prosper
Breeding History in ND
Corn Production
Corn Project Leader
   Publications
   Research
   Teaching
Corn Project Staff
Graduate Students
Objectives
Breeding Methods
   Germplasm Adaptation
   Pedigree Selection
   Population Hybrids
   Recurrent Selection
Corn Releases
   Inbred Releases
   Population Releases
   PVP
   Older releases
   NDSU corn releases after 1979

pedigree selection table

The use of winter nurseries (to a lesser degree greenhouse) to advance three generations per year and extensive testing (15-20 locations per year) of thousands of genotypes (~20,000 plots) across years (three to six years) as well as student exposure to the inbred line development process is a priority for the NDSU corn breeding program. Sample sizes vary from 5500 to 22,500 individuals depending on the population with a maximum of 50 segregating early maturing populations (F2, S0, BC1, and GEM) per year.

NDSU inbred lines

NDSU Inbred Lines (Field Day, Fargo, ND)

S1 and S2 lines eing harvested

S1 and S2 Lines being harvested in Salta (Guachipas Winter Nursery), Argentina

Pedigree selection in corn involved self-pollinating for inbreeding and testing per se (for production purposes) and cross-pollinating to make not only the initial crosses but also to test inbred lines in hybrid combinations for combining ability and release since the end product is a hybrid. At NDSU, approximately 80% of pedigree selection utilizes elite x elite crosses from same heterotic groups, about 5% across heterotic groups, and 15% from germplasm improvement products coming from recurrent selection improved cycles. In the past five years we have released eight early maturing lines.

tobacco drier

Tobacco Drier for S1 & S2 Selections

Guachipas staff

Guachipas Staff (2006-2007)

Kauai Staff (2005-2006)

Choice of germplasm for use as source of inbred lines is essential. At least data from 20+ environments is utilized to select sources. Once they are selected, elite x elite crosses are made in our single-cross nursery and F1s are grown in the greenhouse (no need of this process if germplasm source is an improved population from our recurrent selection program). The following summer thousands of F2 individuals (or S0s) per segregating population. F3 and F4 progenies are grown under drought stress in South America and F3s are crossed for initial hybrid testing to one or two testers in Chile, Puerto Rico, Kauai or New Zealand (new potential site). Early generation testing for complex traits (yield, grain moisture at harvest, root and stalk lodging, test weight, and quality traits) complemented with visual agronomic and disease inoculation and screening across locations has allowed us to select from thousands of potential lines. In addition, every summer we screen for emergence percentage and seedling vigor through a rank-summation index across stages and locations that reduce our pollinations and genetic materials in 10-35% depending on the year effect.
Early and late testcross generation trials as well as single-cross trials focus on General Combining Ability (GCA) during the initial stages of testing and on Specific Combining Ability (SCA) during final stages of testing. Single-cross trials have two broad objectives:

to determine the relative effectiveness of the different recurrent selection methods and line recycling for developing new genotypes than can be used either as hybrids or as germplasm in pedigree selection programs to meet the current standards of the seed industry
to provide training and experience for graduate students in conducting selection within breeding nurseries, planning and conducting the production of single-cross seed, and conducting and analyzing single-cross trials repeated over several environments.

Trials are in, approx. 90% of the cases, based on lattice designs while the rest of them are based upon RCBD and augmented designs. Split-plot arrangements have been used occasionally for thesis studies.

aerial photo of NDSU corn hybrid and recurrent selection trials

Aerial Photo of NDSU Corn Hybrid and Recurrent Selection Trials Arranged in Lattice Designs (Fargo, south of 19^th Ave N)

After years of extensive testing in hybrid combinations as well as intensive selection during the inbreeding process, elite lines are proposed for release. Both the Director and Dean of the AES and the Chair of NDSU Department of Plant Sciences sign to make releases official. Lines are increased for short and long-term cold storage preservation, for Crop science registration, and for PVP protection. As of 2006, NDSU corn inbred lines are not protected by PVP. Distribution of lines is by 50k lots. Most companies have requested seed of all lines released.

inbred trial line

Inbred Line Trial (Field Day, Fargo, ND)

The use of commercial testers within our program has identified specific public-private elite hybrids for the northern Corn Belt. In addition, molecular and field data have suggested that most ND lines have good combining ability with lines derived from several heterotic groups. As a consequence, several companies have requested seed of ND lines for additional testing and their incorporation into private breeding programs. Three agreements were developed by North Dakota Research foundation (NDRF) for this purpose: material transfer agreement, inbred corn research and development agreement, and commercialization and license agreement for managing NDSU corn intellectual property. DNA fingerprinting with SSR markers is carried out on potential lines for NDSU copyright activity control and molecular markers have been useful to demonstrate genetic differences among inbred lines. Inbred trials have been conducted with the purpose to measure all traits needed for PVP protection. Multiple data were often collected for PVP requirements (24 observations per line, over 35 traits per plot, over 40 lines per year.